Revert "Stacking PCBs doesn't work. Too imprecise. THICK PCB could solve it."

This reverts commit 490f224e26ced886a5e1a4095987a5f097893897.
Revert "Drill-size issues again..."

This reverts commit 78704ad755869ccbc9e371843dd45850562db76e.
Revert "Added sub-boards to triple board thickness for better  pogo-pin alignment."

This reverts commit 808a31bfee8c9cebc64c52d68362d3861d50fe81.